Uncia (coin)

From Wikipedia, the free encyclopedia

The uncia, a Latin word used for a twelfth of anything, was a unit of length (equivalent to an inch, one-twelfth of a pes or foot) and of weight (equivalent to an ounce, one-twelfth of a libra or pound).

By derivation, it was also the name of a bronze coin valued at one-twelfth of an as produced during the Roman Republic. The uncia had a theoretical weight of about 27 grams under the libral standard and was produced occasionally towards the beginning of Roman cast bronze coinage. Obverse types of the uncia include a knucklebone (ca. 289-245 BC), a barleycorn (ca. 280-245 BC), and the helmeted bust of Roma (from ca. 240 BC).

In imperial times the uncia was briefly revived under Trajan (98-117) and Hadrian (117-138). This coin was about 11-14 mm in diameter and weighed about 0.8-1.2 grams. It featured the bust of the emperor on the obverse with no inscription and "SC" (for Senatu Consulto) in a wreath on the reverse. If this issue belonged to the imperial system, meaning it was not a provincial piece, it would be an uncia. This issue may have been made only for circulation in the East.

See also: Roman currency, Roman Republican coinage.